In general, in communications circuits, a plurality of high frequency signals are combined as one signal or bound as one to thereby establish communications means such as multiband systems via connection with other circuits.
When the plurality of signals are connected and used on one line, problems in which the signals are offset from one another or loss thereof is caused due to division thereof, depending on respective signal characteristics may occur.
Thus, peculiar antennas for each signal have been used or filters for filtering noise or the like have been installed, such that there have been negative attributes such as a complex structure, an increase in a size of a circuit, and the like.
Thus, the present applicant has proposed a method for controlling a current to only flow in a desired direction by controlling a high frequency signal current to flow in a predetermined direction on a metal plate using electro-polarization, and an antenna using the same, in Korean Patent No. 10-1017690 (Electro-polarization and Application thereof, hereinafter, referred to as ‘the related art’). Here, in the related art, when a high frequency signal is divided into a positive (+) signal and a negative (−) signal according to a polarity and two signals are applied to a metal plate, two signals are applied thereto to be connected to each other while maintaining a predetermined time interval therebetween. Thus, an effect that an application direction of the current is constant so as to allow the current to constantly flow only in a current application direction along an axis at which the current is applied may be obtained. Here, a combiner combining a plurality of signals with each other so as to provide the plurality of signals as one signal, using the effect as described above, or the like, is used, so that respective input signals may not be transferred to different input ports, but may only be transferred to an output port, thereby providing a technology in which the combiner is used as a combination circuit having excellent isolation between input ports and loss due to a signal combination is prevented.
Although the antenna technology of application thereof, according to the related art described above, in which the structure thereof is simplified and the effect thereof is excellent, has been provided, the development of a directional multiple-input multiple-output (MIMO) antenna in which more effective transmission and reception may be obtained by maintaining directivity in which a relatively large amount of transmission is maintained without signal offset, has also been required. Further, a technology for implementation thereof with a simplified structure has been required.
Related Art Documents are as follows.
European Patent Application No. 98102456.5 (Filed Aug. 18, 1999)
European Patent Application No. 10168363.9 (Filed Jan. 5, 2011)
Korean Patent Laid-Open Publication No. 10-2009-0057350 (Published Jun. 5, 2009)